Traditional morphologic and cytologic methods, which are expensive and uncomfortable, fail to detect a sizable portion of bladder cancer cases or recurrences early enough to impact significantly upon patient survival. Molecular methods to detect genomic instability are beginning to play an increasing role in determining the critical genetic changes associated with transitional cell carcinoma (TCC) of the bladder. The analysis of genomic instability, caused by loss of heterozygosity or microsatellite alterations, is a powerful new and sensitive technique. This Phase I study is designed to establish the merit and feasibility of using the DNA-based approach to detect genomic instability and identify early or recurrent bladder cancer in exfoliated cells. We will analyze PCR-amplified DNA from paired (blood and urine) samples. Twenty markers, which can detect 95% of all primary bladder cancers, will be utilized to determine the presence of either microsatellite instability of loss of heterozygosity. Our long-range goal is to further develop and improve the molecular staging assay to increase throughput and cost-effectiveness. This sensitive assay has enormous potential as a rapid, low-cost, safe screening tool for early and recurrent bladder cancer.